Let's establish some facts: this is a common experience with WRXs and STIs. My 2017 WRX does it too. It doesn't have anything to do with rubbing on plastic, side skirts, wheels lifting or anything like that. It has nothing to do with traction control settings. So what is it? Anyone who owns a 4x4 with a locking center differential can duplicate this... i.e. my Toyota Land Cruiser fully locked-up will do the same thing. My conclusion: The all-wheel-drive system on WRXs and STIs allows so very little differential speed between each wheel, that it acts like it is almost fully locked up all the time. Which make it one of the best non-truck or SUV vehicles for snow driving (except for the low clearance).